stake



(Model.)

E. T. STARR.

Dental Hand Piece.

Patented Oct. 26, 1880.

By his Harney/.s- ,Mr/D

muumummsk. WASHINGTON n c UNITE STATES PATENT Fries.

ELI T. STARR, OF PHILADELPHIA, PA., ASSIGNOR TO JAS. W. WHITE, J. CLARENCE WHITE, AND H. M. LEWIS, AS TRUSTEES, OF SAME PLACE.

DENTAL HAND-PIECE.

SPECIFICATION forming part of Letters Patent No. 233,708, dated .October 26, 1880.

Application filed July 29, 1880.

To all whom t may concern Be it known that I, ELI T. STARR, a citizen of the United States, residing in the city and county of Philadelphia, in the State ot' Pennsylvania, have invented certain new and useful Improvements in Dental-Engine Hand- Pieces and Tools therefor, (Gase G,) ot' which the following is a specification.

My invention relates to dental engines ot the class embodying in their structure a motive power, a flexible rotary shaft driven by said power, and a hand-piece affording bearin gs for a spindle-chuck, connected at its rear end with the outer or free end of saidshaft, so that the operating-tool driven by said chuck may be moved freely about in different directions by the hand which grasps the hand-piece, in order to permit said tool to be directed to the point at which it is to do its work without interfering with the free transmission of the drivingpower.

The object of my present invention is, rst, to improve the construction of the hand-piece, so that wear of the chuck in the casing of the hand-piece may be readily compensated, and unsteady movements or wabbling of said chuckprevented without interfering with its free rotation upon its longitudinal axis; second, to improve the tool-lookin g devices ofthe spindlechuck, so as to permit rapid and easy insertion and removal ofthe operatin g-tools in the socket ot' said chuck, while rmly and securely locking said tools therein against endwise movement when at work; and, third, to improve the construction of the shanks of the operating-tools, so that any wear which may occur between them and the chucksocket may be compensated, in order to prevent all unsteady motion or lateral vibration of the tools in the socket of the chuck while at work, whereby the operations of the dentist may be performed with greater ease, nicety, and skill, with a saving` of time to the operator, while avoiding all noise disagreeable to the patient.

The subject-matter claimed is recited at the close of the speciiication.

The accompanying drawings represent my present improvements as embodied and organized in the best way now known to me. It

(Model.)

will be understood that some of my improvements may be used without the others.

In said drawings, Figure lis a longitudinal central section through the hand-piece casing and front end of the spindle-chuck mounted therein, on an enlarged scale, to show the entire apparatus. Figs. 2, 3, and 4. are, respectively, transverse sections through the handpiece on the lines 2 2, 3 3, and 4 4 of Fig. l; and Fig. 5 is a view, in elevation, of a dental operating-tool constructed according to my invention and adapted to be inserted in and driven by the spindle-chuck shown in Fig. l.

The hand-piece casing A is shown in this example as constructed of four tubular sections-that is, it is shown as consisting of a handle-section, a, having a detachable hardmetal nose, which gives bearing to and envelops the front end of the spindle-chuck B of a section, a', connected with the handle-section by screw-threads, so as to be removable, and affording the bearing for the rear end of the spindle-chuck; ot' a section, a2, which is connected with the butt-end of section a oy screwthreads, so as to permit disconnection of said sections a a2, to permit access to the adjustable collar b on the rear end of the spindle` chuck, and of a shank-section, a3, which is connected with the section a2 by a swivel-joint, a, ot' well-known construction, in order to permit the handle-section, which is grasped by the hand, (being ordinarily held centrally of the fingers and thumb of the operator, somewhat after the fashion of holding a pen or pencil,) to be turned relatively to said shank-section around the spindle-chuck, so as to conform to the turning movements ofthe operators hand in manipulating the tool.

The shank-section a3 is connected with the spindle-chuck in its bearings in the hand-piece casin 0f. The said iiexible shaft and its flexible enveloping sheath may be similar to those shown in Letters Patent heretofore granted to me September 2, 1879, and November 25, 1879, numbered, respectively, 219,320 and 222,093; but as neither they nor the particular organization of engine used constitute the subject matter claimed by me herein, it is unnecessary to illustrate them in the drawings or describe them here in detail.

The front end ofthe chuck B is socketed, as usual, and is reduced in size, andhas its bearing in the nose ot' the handle-section a of the Ycasing A, while thc rear end of the chuck Yis extended throughvthc section a', so as to have its rear bearing therein. An annular collar or ring, b, is iitted to and fastened upon the end of the spindle-chuck by a set-screw, preferably, so as to abut against the annular shoulder formed by the butt-end ot' the section a of the casing, and it constitutes the pullbearing of the chuck-that is, it constitutes a bearing which prevents the endwise forward movement of the chuck in the casing when a pulling or draw cut is being made with the tool; A similar collar, b, is screwed vupon a male screw, b2, formed upon the spindle-chuck in front ot' the front end of the said casingsection a', so as to be adjustable, (it being fastened when adjusted by a set-screw preferably,) and it constitutes the thrust-bearing of the chuck-that is, it constitutes a bearing which prevents the endwise backward or inward movement ofthe chuck in the casing when a thrust or pushing cutis being made with the tool, whereby it will be seen that no endwise movement of the chuck inthe casing c'an take place, while, as wear occurs between the'parts, it can be taken up or compensated for by the adjustment of the collars above described. The said collars are made detachable as well as adjustable, so as to be readily renewed when required.

interposed between the xed thrust collar or bearing b and the casing-section a is a hard-metal loose supplemental conical t'riction thrust-bearin g, b3, the conical or tapering end of which ts a similar seat in the front end ot' said casing-section a', as clearly shown in Fig. 1. The said hard-metal conical bearing b3 affords a plain annular shoulder in front for the collar b to work against, while the conical portion of said bearing tits the casesection a and prevents wear ot' said section, being prevented from turning with the chuck by the friction between its conical end and said case-section.

By the employmentoftheloosesupplemental hard-metal conical thrust-bearin g b3 not only is wear ofthe soft-metal casing-section a prevented, but the ready substitution of a new bearing in place ot' one which has become worn upon its front face is also permitted. This avoids the necessity, in order to prevent wear and permit renewal of the worn parts, ot' such a construction as is shown, for example, in Johnston and Brownes patent of March 25,1879, which exhibits the casing-section as provided with a fixed steel face, a loose friction -ring being interposed between said face and the thrust-bearii'ig or collar of the chuck to receive the thrust and friction when a pushing` cut is being made with the operatin g-tool.

It will be noticed that achamber,c, is formed between the front end ot' the spindle-chuck andthe end of the casing-nose, through which v the tool-shank is inserted, and this is for the purpose of arresting the passage into the front bearing and chuck-socket of saliva, grit, &c., when taken up by the revolution of the tool, and, furthermore, to prevent the exudation ot' oil from the front bearing to soil the lingers of the operator or face of the patient; but as this is the invention of Dr. T. S. Phillips, patented September 23, 1879, it, of course, forms no part of the invention claimed by mc.

The shank ofthe operating-tool D, adapted to my improved hand-piece, as organized in the presentinstance, is provided with astraight cylindrical bearing portion, d, terminating in rear in a shoulder, df, (preferably a round shoulder,) and with areduced portion, d2, having an annular concave groove, notch, or recess, 013, with which the tool-locking` devices engage, as will be fully explained.

rlhe portion d4 of the tool-sha-nk in front of the cylindrical portion d is preferably reduced in size as compared with said cylindrical portion, and terminates at the front end iu the cutting-burr, drill, or other operating-point d5, commonly employed for dental operations.

In practice I contemplate constructing the operating-tool either in a single piece, as has heretofore been customary, or in sections, one section consisting` of the portions d d cl2 and the other section ofthe operating-point d5, with a short shank or extension, d4, fitting a socket in the front end of the cylindrical portion d, as shown in section in Fig. 1, the two sections of the tool being rigidly united in any lsuitable way-for instance, by a transverse pin, d, as shown in Figs. 1 and 5. The inner end of the cylindrical portion d ot' the toolshauk-in this instance commencing at the round shoulder d-is provided with a spiral groove, dl, with which a lip, lug, or projection,

e, in the mouth of the socket of the spindlechuck engages when the tool is insertedin said socket and turned in the proper direction, as shown in Figs. l and 2, the object of which is to fasten the tool in the chuck securely against lateral movement and to compensate or take up any wear that vmay occur between the tool and socket.

The cylindrical portion of the tool, it will be seen, lits snugly the mouth of the chucksocket as well as the opening in the nose of the hand-piece casing, through which the toolshank is inserted into said socket, so that said cylindrical portion of the tool has a bearing to support it in advance of the chuck.

rlhe tool is locked from turning in the socket IIC when inserted therein, and its groove engaged by the lip or projection e by tool-locking devices, which prevent endwise'movement of the tool.

rIhe devices are shown as consisting of two plate or flat springs, E E, fastened at their rear ends directly opposite each other in longitudinal recesses in the chuck, and having a tendency at their front ends to move outward or laterally when not compressed by a sleeve or thimble, F, surrounding the chuck and movable endwise thereon.

The front ends ot' each of the laterallymovable locking-springs is provided with a lug projecting into va lateral opening intersecting the bore or socket of the chuck, and each of said lugs is concave on its inner face, to encircle and t, when compressed, the concave groove or notch in thetool-shan k. Said sleeve F is thrust f'orward to compress the lug-nosed tool-locking ends of the springs E E by means of a coiled spring, E', also surrounding the chuck, and compressed between the fixed collar b at rear and the annular shoulder formed by the butt-end of the sleeve at front, the

I force of this spring E being exerted at all times to thrust the sleeve forward to compress the laterally-yielding locking devices into engagement with the groove or notch of thetoolshank, as clearly shown in Fig. 1.

It will be obvious, therefore, that when a tool is inserted in the socket and it is desired to withdraw it, the sleeve F must be retracted against the force ot' spring E', so as to permit the locking ends of the springs E E to move outward, which enables the tool to be turned and moved endwise, and this retraction of the sleeve I accomplish by means of a lever or finger-piece, G, pivoted to or between suitable lugs on the exterior of the casing, the front end of the lever. being provided with a lip or extended end, g, which works through an opening,f, in the side of the casing, and engages, when the rear end of the lever is raised, with an annular shoulder,f', on the sleeve, to retract it as the lip g of the lever moves backward around the pivot of the lever.

A. light plate-spring, g', is fastened to the casing and acts upon a cam-edge of the lever, to hold it down closely to the casing and maintain itin a position with its lip g out of the way vof the sleeve F, so as not to interfere with the turning movements of said sleeve with the spindle-chuck which it surrounds when the tool is at work.

It will be noticed that I have so organized the lever G, which actuates the tool-locking devices, that itis raised in a forward direction and moves the controlling-sleeve F backward to permit the tool-locking devices to move laterally to release the tool, and this capacity ot the lever to be lifted or moved forward to operate the tool-locking devices is a very valuable one in the manipulation of a dental-engine hand-piece, rendering its operation easy and rapid, enabling the thumb or nger ot' the hand that holds the hand-piece to be used to work the lever, whilethe other hand is at the same time free to relnove or insert the tool.

It will also be noticed that I have so organized an external pivoted or rocking lever with a hand-piece to manipulate the tool-locking devices as not to interfere with the ready disconnection or removal ofthe handle-section ot' the casing, in order to expose the chuck-hearings for oiling, it being unnecessary, in other words, to first remove the lever G in order to gain access to thc chuck-bearings to clean or oil them.

In an application iiled by me August 16, 188i), I have shown and claimed an operatingtool having a shoulder to determine itsfextent of movement into a tool-holder socket and a locking-notch at its driving end provided witha tapering Irear wall. In said application I have also shown and claimed a dental-en gine handpiece provided with a socketed spindle tool-holder having a seat or enlarged mouth for the recept-ion ot' a shoulder on the shank of an operating-tool, and with a toollocking device capable of moving laterally, only having a tapering lug to engage the toolshank to lock said shank in the socket while exerting a drawing action, so as to force the shoulder of the tool rmlyin its seat in the toolholder. In so far, therefore, as these specific con structions of tool and hand-piece may be said to be shown in this present case, I disclaim them herein in favor of my said application of August 16, 1880, reserving, however, as the subject-matter of this case all other patentable subject-matter common to the two applications.

I claim as my invention- 1. The combination, substantially as hereinbefore set forth, of the sectional casing, the spindle-chuck, the respective adjustable collars constituting the pull and thrust bearings of the chuck, and the loose conical supplemental thrust-bearing fitting a correspondingly-formed seat in the casing.

2. The combination, substantially as hereinbefore set forth, of the hand-piece casiughaving a detachable handle-section, the spindle-- chuck, the tool-locking devices carried by said chuck, and a lever pivoted externally on the casin g and operating through an opening therein to move the tool-lock, while capable of being rocked upon its pivot, so as not toafford any obstruction to the ready removal of said handle-section.

3. The combination, substantially as hereinbefore set forth, of the casing, the spindlechuck, a laterally-movable tool-locking` device carried by said chuck, the sleeve to compress said locking device, the spring acting to thrust said sleeve forward, and a lever pivoted externally on the casing and engaging said sleeve to move it in a backward direction, to permit said locking device to move laterally to release the tool, while capable of being IOO IIO

ITS

rocked upon its pivot out of contact with said sleeve, so as to ot'f'er no obstruction to the free revolution of' the chuck.

4. The combination, substantially as hereinbefore set forth, of the casing, the rotary spindle-chuck. two laterally-moving devices carried by said spindle-chuck and arranged so as to operate upon the tool-shank from opposite sides, the endwise movable sleeve, the spring acting upon said sleeve to thrust it forward to compress said locking devices, and the pivoted lever to retract said sleeveto permit of the removal or insertion of an operating-tool.

5. An operating-tool constructed, substantially as hereinbet'ore set forth, with a straight cylindrical bearing portion terminating in a shoulder, and a reduced portion in rear of said cylindrical portion provided with a locking groove or notch.

6. An operating-tool constructed, substantially as hereinbef'ore set forth, with a spiral groove, and with a separate locking notch or recess for the engagement of the too11ocking devices 0f a rotary chuck.

7. The combination, substantially as hereinbefore set forth, of the rotary chuck, the lip or projection in the socket thereof, the toollocliing devices of said chuck, and an operating-tool having a spiral groove for the engagement of said lip in the chuck-socket, and a notch or groove for the engagement of said tool-locking devices.

In testimony whereof I have hereunto subscribed iny naine.

ELI T. STARR.

Vitnesses:

GEORGE l). MORGAN, WILLIAM H. GILBERT. 

